Technical Field
The present invention relates to an ink composition, an ink container, a set of an ink composition and an ink container, and a recording apparatus.
Related Art
In the related art, there has been known an ink jet recording apparatus which records images or the like on a recording medium with minute ink droplets discharged from nozzles of a recording head for ink jet recording. The ink jet recording apparatus includes an ink container (for example, an ink cartridge) for supplying an ink composition to the recording head.
As such an ink container, there has been known a refill (pouring) type ink container (a so-called continuous supply type ink container) in which a continuous supply type ink container is refilled with an ink composition instead of replacing the ink container, as well as a replaceable ink container (a so-called ink cartridge) in which the ink container itself is replaced, when an ink composition in the ink container is equal to or less than a predetermined amount. For example, in JP-A-2012-148511, there is disclosed an ink jet recording apparatus which supplies ink from a continuous supply type ink tank to an ink jet head through an ink supply tube, and the ink tank has an ink-refillable structure.
However, the continuous supply type ink container disclosed in JP-A-2012-148511 is a so-called atmosphere open type container in which an ink chamber is opened to the atmosphere.
Thus, an interface (gas-liquid interface) between the air present in the upper side of the ink chamber and the ink is generated in the ink chamber of the container. Since the ink composition used in such an ink container easily dries at the gas-liquid interface, aggregates derived from components included in the ink are easily generated at the gas-liquid interface. That is, when moisture or the like evaporates from a thin film generated at the gas-liquid interface, the solid content in the ink aggregates to form aggregates. Particularly, when the wettability of ink to a material constituting the inner wall of the ink chamber is high, the area of a thin film formed at the contact portion of the inner side of the wall and the liquid surface of the ink is increased and the thickness thereof is reduced, and thus, the degree of the generation of aggregates becomes higher. The recording head of the ink jet recording apparatus has a mechanism in which ink droplets are discharged from minute nozzles, and thus, when the aggregates reach the nozzles, the nozzles are clogged and the quality of a recorded image is deteriorated. Therefore, a filter for capturing foreign substances such as aggregates is usually provided in a flow path for supplying ink to the nozzles so that the foreign substances do not reach the nozzles. However, when a large amount of foreign substances is accumulated in the filter, the amount of ink supplied to the recording head is reduced and normal recording is interrupted.
Further, since the continuous supply type ink container which can be refilled with ink has a significantly large gas-liquid interface area and a significantly large number of contact portions between the inner side of the wall and the liquid surface of the ink, and has a very long period of use, compared to the cartridge type ink container, aggregates are easily generated in a large amount or frequently, and inconveniences such as ink supply failure due to the aggregates captured by the filter or the like become apparent easily.